High gloss and/or high DOI coatings are widely utilized in the coatings art. The automotive industry has made extensive use of such coatings, often as color-plus-clear composite coatings for automotive body panels. Such coatings are especially susceptible to a phenomenon known as environmental etch. Environmental each manifests itself as spots or marks on or in the high gloss or high DOI finish of the coating that often cannot be rubbed out.
It is often difficult to predict the degree of resistance to environmental etch that a high-gloss coating will exhibit. Many coating compositions known for their durability and/or weatherability when used in exterior paints, such as high-solids enamels, do not provide the desired level of resistance to environmental etch when used as high gloss or high DOI coatings.
Many compositions have been proposed for use as the high gloss coatings, such as polyurethanes, acid-epoxy systems and the like, However, many prior art systems disadvantages such as coatability problems, compatibility problems with underlying coatings, solubility problems, Moreover, very few one-pack coating compositions have been found that provide satisfactory resistance to environmental etch, especially in the demanding environment of automotive coatings. Thus, there exists a continuing need for curable coating compositions that provide satisfactory resistance to environmental etch when used as high gloss and/or high DOI coating.